JP2886433B2 - Bonding method for fixing ballast under railway tracks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive method for fixing ballast under a railway line, and more particularly, to a two-component urethane adhesive capable of exhibiting excellent quick-setting and flame-retardant properties and its main agent and curing. The present invention relates to a bonding method in which an agent is spray-mixed to foam and cure.

[0002]

2. Description of the Related Art Ballasts laid under railway tracks
(Pebble and gravel) are fixed and held with an appropriate adhesive in order to prevent them from being scattered by wind pressure or other external force when passing through the train. Conventionally, an emulsion adhesive or an epoxy adhesive has been used for such ballast fixing. By the way, emulsion adhesives can be easily applied for one liquid, and have the advantage of being inexpensive.However, due to drying and curing by water evaporation, the time required for curing is extremely long, and is easily affected by the weather, Also, heat resistance is low. On the other hand, epoxy-based adhesives have better curability than emulsion-based adhesives, but have a toxic problem such as rash because the cured film is hard and amine is used as a curing agent. Could lead to

[0003]

[Problems to be Solved by the Invention] Including the conventional problems described above, the problems in the ballast fixing application include: (1) low toxicity in consideration of the possibility of flowing under overhead lines; (2) renovation and repair (3) It must be fast-hardened without being affected by the weather at the time of construction. ) It must be flame-retardant to the sparks when polishing the track and the heating burner used to adjust the length. (5) It must be cured within 3 to 4 hours to be able to cope with trains due to night work. Become.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive research focusing on two-part urethane-based adhesives with the aim of achieving the object, the following findings were found, and the present invention was completed. Concerning the toxicity of (1), a urethane prepolymer base agent whose oral toxicity can be practically non-toxic and water as a curing agent are combined.
Regarding the adhesion between the ballast surface layers (2), the carbon dioxide gas is generated during the curing process of the urethane prepolymer and water, and only the surface layers are foamed and cured by spray mixing of both components. As a countermeasure against the weather (3), particularly rain, select a composition that requires water in the curing process, that is, a combination of a urethane prepolymer main agent and a water curing agent. Regarding the flame retardancy of (4), flame retardancy is imparted by using a melamine-modified polyether polymer as a polyol component of the urethane prepolymer main component. The rapid curing of (5) is further improved by adding urea or thiourea as a curing catalyst to a water curing agent.

That is, the present invention relates to a bonding method for fixing a ballast under a railway line, comprising: (a) a polyether polyol containing at least an ethylene oxide part;
(b) a melamine-modified polyether polyol is used in combination, and a main agent comprising a terminal isocyanate group-containing urethane prepolymer obtained by reacting an organic polyisocyanate compound with them, and water as a curing agent are spray-mixed, foamed, An object of the present invention is to provide a bonding method characterized by being cured.

In the present invention, a polyether polyol is a compound containing two or more active hydrogens (eg, ethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol, polyethylene glycol, polypropylene glycol, glycerin, trimethylol). A compound obtained by addition polymerization of alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) to propane, 1,2,6-hexanetriol, etc.

The polyether polyol containing at least ethylene oxide moiety (hereinafter referred to as EO) used in the present invention
(Contained polyol) (a) is one using at least ethylene oxide as the alkylene oxide in the polyether polyol, usually, the content of ethylene oxide portion (hereinafter, referred to as EO rate) is 15 to 4
What is set to 0% (% by weight, the same applies hereinafter) is appropriate. If the EO ratio is less than 15%, the obtained terminal isocyanate group-containing urethane prepolymer has reduced hydrophilicity,
If it interferes with the curing reaction with water and exceeds 40%,
The water resistance of the cured film tends to decrease. As a specific example of such an EO-containing polyol, a polyether diol obtained by addition-polymerizing ethylene oxide to polypropylene glycol, which is manufactured by Asahi Denka Kogyo KK, "ADEKA POLYETHER P
R-3007 "(molecular weight 3000, EO ratio 30%) is commercially available.

Melamine-modified polyether polyol used in the present invention (hereinafter referred to as melamine-modified polyol)
(b) refers to a product obtained by dispersing melamine in the above polyether polyol, or a product obtained by adding melamine in a polyol molecule in the production process of a polyether polymer, and is usually 100 parts of polyether polyol.
(Parts by weight, the same applies hereinafter) the amount of melamine is 5 to 30 parts,
Preferably, 10 to 25 parts may be used. Specific examples of such a melamine-modified polyol include those having a molecular weight of 5
80% polyether triol 80% melamine 20
% M-95 manufactured by Asahi Glass Co., Ltd.
"0" is commercially available.

The terminal isocyanate group-containing urethane prepolymer (hereinafter referred to as terminal N
The EO-containing polyol (a) and the melamine-modified polyol (b) are usually 6/4 to 9
/ L in combination with an organic polyisocyanate compound in a weight ratio of from 0.1 to 90 ° C in the presence of an appropriate reaction solvent, if necessary, so that the NCO / OH ratio becomes 4.5 to 5.5.
It is produced by reacting at a temperature of Examples of the organic polyisocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, and 1,3. -Cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,
3-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl 2,4
-Cyclohexane diisocyanate, methyl 2,6-cyclohexane diisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-
Diphenyl diisocyanate, 1,5-naphthalenediisocyanate, 4,4′-diphenylmethane diisocyanate, crude diphenylmethane diisocyanate,
2,4- or 2,6-tolylene diisocyanate, 4,
4'-toluidine diisocyanate, dianidin diisocyanate, 4,4'-diphenyl ether diisocyanate, 1,3- or 1,4-xylylene diisocyanate, ω, ω'-diisocyanate-1,4-diethylbenzene, and the like. 4,4'-Diphenylmethane diisocyanate is preferred.

As the curing agent in the present invention, water alone or preferably a curing catalyst (eg, urea, thiourea, etc.)
Water containing 3 to 40% is used. The addition of such a curing catalyst can further improve the quick-curing property.

The two-part urethane adhesive used in the present invention comprises the above terminal NCO prepolymer base and a water curing agent in a weight ratio of usually 10: 1 to 1: 1, preferably 3: 1 to 1: 1. It is configured by using. If necessary, a normal solvent (e.g., liquid aliphatic saturated hydrocarbons having a boiling point of 160 to 300 ° C, liquid aromatic hydrocarbons having a boiling point of 150 to 200 ° C, etc.) and a plasticizer (e.g., dibutyl phthalate, Dioctyl phthalate, alkylbenzene, etc.),
Various auxiliaries such as stabilizers (eg, benzotriazoles, regio hindered amines, etc.) and coloring agents may be added in appropriate amounts.

In order to carry out the bonding method of the present invention using such a two-component urethane adhesive, the main agent and the curing agent are spray-mixed, and for example, the main agent and the curing agent are mixed in the air using a two-head spray gun. While applying to the object to be coated (air mixing method), or after applying the main agent with an air spray gun, a curing agent is applied on the main agent (after spray method). In this way, the main agent and the curing agent foam and cure,
When applied to ballast fixation under a railway line, foaming and hardening only in the ballast surface layer can be performed.

[0013]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Example 1 400 g (3.2 equivalents) of main agent 4,4'-diphenylmethane diisocyanate (Sumitomo Bayer, Sumidur 44S)
Is melted at 80 ° C. and the EO-containing polyol is stirred
(Adeka Polyether PR-300 manufactured by Asahi Denka Kogyo Co., Ltd.)
7, molecular weight 3000, EO ratio 30%) 800 g (0.53
Equivalent) and a melamine-modified polyol (M-9 manufactured by Asahi Glass Co., Ltd.)
50, 80% of polyether triol having a molecular weight of 5000
/ Melamine 20%) 200 g (0.12 equivalents)
Let react for hours (NCO / OH = 4.8-5.0%),
NCO content 7.5 ± 0.3%, viscosity 5000 cps / 2
A 0 ° C. terminal NCO prepolymer is obtained. Curing agent A water curing agent consisting of water / urea / thiourea (75: 18: 7) (weight ratio) is used. The adhesive consisting of the main agent and the curing agent = 2: 1 was spray-mixed with a ballast stone as an object to be coated by an aerial mixing method, and then left at room temperature to form a cured film in 5 minutes. When an epoxy-based adhesive was used, it took 4 hours to cure. next,
A combustion test specified in JIS D1201 was performed using the above main agent and curing agent, and the results are shown in Table 1 below.

Comparative Example 1 In the preparation of the base material of Example 1, 345 g of 4,4'-diphenylmethane diisocyanate (Sumidur 44S) (2.
76 equivalents) and an EO-containing polyol (ADEKA polyether P)
(R-3007) 800 g (0.53 eq.)
Except for CO / OH = 5.24), a terminal NCO prepolymer having an NCO content of 7.5 ± 0.3% and a viscosity of 4000 cps / 20 ° C. is obtained in the same manner. Next, in Example 1
Combustion tests were conducted using the same curing agents in the same manner as described above, and the results are shown in Table 1.

[0015] From the results in Table 1, it was found that the adhesive of Example 1 had improved flame retardancy as compared with that of Comparative Example 1.

[0016]

According to the bonding method of the present invention having the above-described structure,
It is useful for ballast fixation under the railway track, and all the problems that could not be achieved in the past, such as low toxicity, fixation only between the ballast surface layers, fast curing, not affected by rain, and flame retardancy, etc. Can be satisfied.

Continuation of the front page (56) References JP-A-6-263835 (JP, A) JP-B-45-9957 (JP, B1) Keiji Iwata, "Polyurethane Resin Handbook", Nikkan Kogyo, September 25, 1987 Published by Shinbunsha, pp. 437-492 and 535-570

Claims (4)

(57) [Claims] 1. An adhesive method for fixing a ballast under a railway line, wherein (a) a polyether polyol containing at least an ethylene oxide part and (b) a melamine-modified polyether polyol are used in combination, and A bonding method characterized by spray-mixing water as a curing agent with a main agent comprising a terminal isocyanate group-containing urethane prepolymer obtained by reacting a polyisocyanate compound, followed by foaming and curing. 2. An adhesive method for fixing a ballast under a railway track, wherein (a) a polyether polyol containing at least an ethylene oxide portion and (b) a melamine-modified polyether polyol are used in combination, and A bonding method comprising applying a main agent comprising a urethane prepolymer having a terminal isocyanate group obtained by reacting a polyisocyanate compound, and then applying water as a curing agent on the main agent to cause foaming and curing. 3. The weight ratio of the main agent to the curing agent is 10: 1 to 1:
The bonding method according to claim 1, wherein the bonding method is 1. 4. The bonding method according to claim 1, wherein the polyether polyol (a) has an ethylene oxide content of 15 to 40% by weight.